1. Field of the Invention
The present invention relates to an agent containing creatine, creatinine and/or their derivatives for the purpose of hardening, improving the luster of, fortifying and improving the structure (restructuring) or increasing the volume of keratinic fibers, particularly damaged keratinic fibers such as damaged human hair.
2. Description of the Related Art
The damaging of keratinic fibers by environmental factors (for example energy-rich radiation), the physiological status (for example age or health of the individual involved) or mechanical and chemical effects is known. The consequences are unfavorable mechanical properties of the affected materials. Such damage of the internal structure of keratinic fibers manifests itself by the loss of hardness, luster, strength, breaking resistance, tensile strength or fiber bundle tensile strength.
Keratinic fibers, particularly human hair, show such effects, in particular, through a lack of luster, reduced tensile strength and poor combability. Said effects are brought about by ageing processes, primarily physiologically related ones or induced by physical (weathering), mechanical (combing, brushing) and chemical factors. Long hair shows these effects especially at the hair tips. Chemical factors consist primarily of bleaching, oxidative dyeing and permanent waving of hair, in which aggressive oxidants and reducing agents are used, preferably in a strongly alkaline medium where they exert their full action. However, other chemical factors, for example water containing high amounts of chlorine or salts, also exert damaging effects on keratin-containing material.
Commercial rinses and treatments contain as active substances mainly cationic surfactants or polymers, waxes and/or oils. The more damaged the hair, the more anionic groups are present at the surface. Cationic compounds are electrostatically attracted to such an oppositely charged surface, whereas oils and waxes interact with the hydrophobic groups of keratin. A structural improvement inside the hair therefore cannot be achieved with such hair-care products.
The use of certain unsaturated compounds, particularly ascorbic acid, in hair-treatment agents for this purpose is known from our own WO 00/57839. In aqueous solution, however, ascorbic acid is not stable for a long time so that such agents cannot be stored, but must be prepared only shortly before use.
The use of creatin and creatin derivatives as moisturizers for cosmetic preparations is known from DE-A 198 41 385. Such preparations are said to improve the elastic properties of the skin and to contribute to the smoothing of wrinkles and to the removal of cracks and dandruff.